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Prosthodontics

Occlusion Basics for Board Exams

A simple breakdown of CR, ICP, lateral guidance, and occlusal concepts.

Quick Answers

What is intercuspal position (ICP)?

The position of maximum intercuspation of the teeth, independent of condylar position.

What is centric relation (CR)?

A reproducible joint position where the condyles are in their most anterior-superior position in the glenoid fossa.

What is mutually protected occlusion?

An occlusal scheme where posterior teeth support vertical load and anterior teeth protect posteriors in excursions.

Why does occlusion matter in prosthodontics?

Because incorrect occlusion can cause tooth wear, fracture of restorations, and temporomandibular problems.

1. Why occlusion scares students (and how to simplify it)

Occlusion looks complex in textbooks, but examiners usually test a small group of definitions and patterns. If you can define ICP, CR, guidance, and one occlusal scheme clearly, you already cover most board-style questions.

2. Core definitions you must know

Key occlusion definitions

• ICP: Maximum intercuspation of opposing teeth, habitual bite.
• CR: Joint-guided position with condyles in most anterior-superior position, independent of tooth contact.
• CO–CR discrepancy: Difference between CR position and ICP when patient closes.
• Guidance: How anterior teeth and condyles guide movement in excursions.

3. Anterior guidance and canine guidance

Guidance questions are common in prostho and full-mouth rehab stations.

  • Anterior guidance: Contact of anterior teeth that guides mandible in protrusive and sometimes lateral movements.
  • Canine guidance: Only the canines contact in lateral movement, discluding posterior teeth on working side.
  • Group function: Multiple teeth on working side contact in lateral movement (canine + premolars +/- molars).

4. Mutually protected occlusion

A favourite term in exams, especially in fixed prosthodontics.

Mutually protected occlusion — exam sentence

“In mutually protected occlusion, posterior teeth support vertical forces in ICP, while anterior teeth disengage posteriors during excursions, protecting them from lateral loads.”

This definition shows you understand the sharing of load between anterior and posterior teeth.

5. Occlusion when planning crowns and bridges

Whenever you prepare a crown or bridge, you must think about occlusal contacts.

  • Maintain stable contacts in ICP.
  • Avoid heavy contact on cantilevers or pontics.
  • Check guidance so the new restoration does not interfere in excursions.

6. How to talk about occlusion in OSCE

Use a small script instead of improvising:

OSCE occlusion script

“I will first check the patient’s habitual bite (ICP), then assess if there is any discrepancy from centric relation. I will mark contacts in ICP with articulating paper, check for any interferences in lateral and protrusive movements, and adjust the restoration to maintain stable support but avoid heavy contacts in excursions.”

7. Common exam traps

A few points that often appear in viva questions:

  • Do not confuse ICP with CR — CR is joint position, ICP is tooth contact position.
  • Do not claim all patients have CR = ICP; many have small discrepancies.
  • Remember TMD and parafunction can increase loading on restorations.

8. How DentAIstudy helps

DentAIstudy can turn the “heavy” occlusion chapter into simple exam tools:

  • Flashcards for core definitions (ICP, CR, guidance, schemes).
  • OSCE scripts for checking occlusion after crown or bridge cementation.
  • Short viva answers on mutually protected occlusion and group function.
  • Mini case-based questions linking occlusion to restoration failure.

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References

  • Dawson PE. Functional Occlusion: From TMJ to Smile Design. Mosby; 2007.
  • Okeson JP. Management of Temporomandibular Disorders and Occlusion. 8th ed. Elsevier; 2019.
  • GPT-9. Glossary of Prosthodontic Terms. J Prosthet Dent.